In an engine in recent years, there has been known such a technique that a reduction of a nitrogen oxide (NOx) discharged from the engine and a reduction of a noise and a vibration of the engine are achieved by feeding a high pressure fuel to an injector with respect to each of cylinders by utilizing a common rail type fuel injection apparatus, and electronically controlling an injection pressure, an injection timing, and an injection period (an injection amount) of the fuel from each of the injectors (refer to patent document 1 or the like).